Previous research indicates that young infants readily learn to move an overhead mobile by means of their own footkicks (mobile conjugate reinforcement), and they persist in this instrumental behavior when presented with the nonmoving mobile days or weeks later. Altering the reinforcing context by making changes in the details of the mobile reinforcer (e.g., from 10- to 2-components) produce crying in some infants. Preliminary research indicates that this crying (and its underlying negative affective state) produces accelerated forgetting of the task such that infants who cry do not show retention of the task one week later when those who do not cry continue to perform the conditioned response at above-baseline levels. The present research will continue the investigation of the interaction of negative affect and memory for acquired associations using the mobile conjugate reinforcement paradigm. Negative affect will be produced in young infants by various contextual changes and retention will be measured by assessing the production of the previously trained response at various retention intervals. These studies will provide some of the first direct evidence linking affect and cognition in infancy and, as such, will contribute to our knowledge of early development. In addition, these findings will aid educators, clinicians, and parents in understanding how and why infants adjust (or fail to adjust) to new environments.